Aerogels are a fascinating class of high surface-area, mechanically-robust materials with a broad range of both commercial and fundamental scientific applications. Owing to its highly porous mass-fractal nanostructure, amorphous silica aerogel has been used as a capture agent in NASA's cometary-dust retrieval missions, to control disorder in 3He-superfluid phase transitions, in the fabrication of targets for laser inertial confinement fusion, in low-k microelectromechanical (MEMS) devices, and in Cherenkov nucleonic particle detectors.
In particular, amorphous carbon aerogel has received a considerable amount of attention in recent years owing to its low cost, electrical conductivity, mechanical strength, and thermal stability. Numerous applications have been explored for this material including water desalination, electrochemical supercapacitors, and thermal insulation.
The electrophoretic deposition (EPD) process utilizes electric fields to deposit charged nanoparticles from a solution onto a substrate. Earlier industrial use of the EPD process employed organic solvent solutions and therefore typically generated hazardous waste as a by-product of the process. In addition, the shapes, compositions, densities, and microstructures of materials formed through EPD processes have typically been difficult if not impossible to control, either separately or in combination with one another. Furthermore, templating has been used in EPD processes to control pore positioning and density; however, templating is restricted in that it is limited by the template material. Also, it is extremely difficult to form structures from more than one material. That is to say, typical EPD processes are limited in that they are only capable of forming planar, homogenous structures.